The field of this invention relates to inflation valve assemblies of the plug insert-type. Such valve assemblies have been commonly employed with inflatable balls, such as footballs, basketballs, etc., which include a bladder within an outer covering. The assembly comprises a housing which is sealed to the bladder and provides a passage extending from the outside of the ball to the interior of the bladder, and the passage also includes a chamber which receives the sealing plug. To inflate the ball, an inflation needle is extended into the ball through the plug, usually through a preformed passage. Such valve assemblies are disclosed, for example, in U.S. Pat. Nos. 2,935,320, 3,100,498, 4,311,307, and 4,341,382.
When valves of the plug-insert type are used for balls for vigorous sports such as basketball, football, soccer, etc., as well as in playground balls and punching bags, the valves are subjected to extreme use conditions at both indoor and outdoor temperatures. Further, to keep the balls at the proper air inflation for optimum performance frequent additions of air are required. This means that the inflation needle is repeatedly inserted through the valve plug and removed therefrom under a variety of temperature and weather conditions. It has been found that valve failures resulting in leakage of air through the valve occur primarily because of the deterioration of the sealing plugs. For example, the plugs may take a "compression set," which interferes with the sealing engagement between the outside surfaces of the plug and the valve housing within which it is secured. Even more frequently, the insertion and/or removal of the needle causes tearing or enlargement of the passage through which it extends. This interferes with the self-closing action of the passage on withdrawal of the needle. Although lubrication of the inflation needles by users could help to alleviate the problem, it has not been found practical to instruct users to carry out such lubrication.
One attempt to solve this problem has met with a limited degree of success with respect to a valve used in basketballs. The needle insertion passage of the plug was provided with an enlarged recess or "sump" into which the manufacturer inserted a small quantity of liquid glycerin. Then in the filling of the balls passage of the inflation needle through the glycerin containing sump will provide a lubricant coating on the needle, which will be spread to some extent over the surfaces of the passageway. It was found, however, that the supply of glycerin in the sump is rather quickly used up, long before the end of the useful life of the ball and valve assembly. Further, this sump valve design did not lend itself to use with balls, such as footballs, where the bladders are not bonded to the covers. The glycerin-containing valves therefore have received only limited commercial use.
A plug insert-type valve including a liquid-receiving sump is disclosed in U.S. Pat. No. 2,934,344. As described in that patent, the sump is not used to provide a lubrication action. Instead, the sump is designed to collect liquid plasticizer exuded by the plug which is formed from a plasticizer-containing plastic resin. As described, the viscous plasticizer in the sump provides a sealing action, which assists in maintaining an air-tight seal.